Digital broadband broadcast networks enable end users to receive digital content including video, audio, data, and so forth. Using a mobile terminal, a user may receive digital content over a wireless digital broadcast network. Digital content can be transmitted in a cell within a network. A cell may represent a geographical area that may be covered by a transmitter in a communication network. A network may have multiple cells, and cells may be adjacent to other cells.
A receiver device, such as a mobile terminal, may receive a program or service in a data or transport stream. The transport stream carries individual elements of the program or service such as the audio, video, and data components of a program or service. Typically, the receiver device locates the different components of a particular program or service in a data stream through Program Specific Information (PSI) or Service Information (SI) embedded in the data stream. However, PSI or SI signalling may be insufficient in some wireless communications systems, such as Digital Video Broadcasting-Handheld (DVB-H) systems. Use of PSI or SI signalling in such systems may result in a sub-optimal end user experience as the PSI and SI tables carrying in PSI and SI information may have long repetition periods. In addition, PSI or SI signalling requires a relatively large amount of bandwidth which is costly and also decreases efficiency of the system.
The data transmission in certain digital video broadcast systems, e.g., Digital Video Broadcast-Terrestrial Second Generation (DVB-T2) is defined to be Time Division Multiplex (TDM) and possibly in addition frequency hopping (Time Frequency Slicing). Thus, Time-Frequency slots are assigned to each service. Further, different levels of robustness (i.e. coding and modulation) may be provided for the services.
Considering the foregoing and other signalling factors, a relatively large amount of signalling information is involved. The signalling is transmitted in preamble symbols called P2 symbols following the P1 symbol.
Open System Interconnection (OSI) layer L1 (physical layer) signaling is divided into L1-pre (signalling) and L1 signalling, where L1-pre is of static size while the size of L1 varies as the amount of Physical Layer Pipes (PLPs) varies. L1-pre signalling acts as a key to the L1 signalling by signalling its transmission parameters, i.e., size, code rate, modulation, and the like. To enable the receiver to start receiving services, reception of L1-pre should be possible without other preliminary information than what is obtained from the reception of pilot or preamble symbol P1(including FFT-size, guard interval (GI), Frame type). Therefore, the mapping of L1-pre should be defined uniquely for different system configurations. Further, the signalling should be robust against interference. To obtain robustness against impulse interference, such as, for example, from mobile phones, like GSM bursts, the signalling data should be distributed over several P2 symbols to achieve time interleaving with FFT sizes smaller than 16K (there are 8, 4, and 2 P2 symbols for 2k, 4k, 8k modes, respectively). Also, mapping of L1 and L2 signaling should be defined so that, based on the information obtained from L1-pre, L1 can be obtained and based on L1, the dedicated Physical Layer Pipe (PLP0) carrying (OSI) layer L2 (data link layer) signalling can be obtained.
As such, improved techniques for transmission and reception of L1 and L2 signalling in digital video broadcast system preamble symbols would advance the art.